Process Automation - Authorizations for end users

Dear community,

I did not find a suitable answer for my question yet.

Here is our scenario: We have two different automated processes for different user groups. Both have a workflow trigger via a form. We linked the two processes in our on-prem launchpad. So for the tile I can give authorizations to the users who should see which tile and can start which process. Both processes are only a link to the BTP.

But within the process itself I don't know where to control which user can start / use which process. We work here with the role collection "ProcessAutomationParticipant".

Where can we access which user can start which process? When the different user groups would change the URL they could start both process at the moment.

Best Regards

Mathias